In addition to being compact and thin, a high waterproof performance has also been in demand for housings of portable phones and some other electronic apparatuses. Listed below are two sealing methods of providing housings with a waterproof structure.
The first method involves interposing a rubber seal between two cases which are to be joined while opposing each other to constitute a housing. This rubber can be compressed from the sides to work as a seal. The second method involves using a binder or a double-sided adhesive tape to assemble the cases.
With the first sealing structure, it is difficult to realize desired compact and thin housings for the apparatuses, because the housings have to be robust enough to withstand the rubber compression. When a housing gets deformed, for example, due to the high compression of the rubber, liquid may enter the interior of the housing.
As for the second sealing structure, when the bonding surfaces of these two cases get partially separated, for example, due to the deformation of the housing, liquid may also enter the interior of the housing.    [Patent Document] Japanese National Publication of International Patent Application No. 2010-537240    [Patent Document] Japanese Laid-open Patent Publication No. 08-151558    [Patent Document] Japanese Laid-open Utility Model Publication No. 06-34762    [Patent Document] Japanese Laid-open Utility Model Publication No. 06-69246